- Joined
- Feb 28, 2019
- Messages
- 530
Using my Deckel to sharpen small drills. It's quite a challenge to get the cutting edges lined up with vertical. So I decided to make a see-thru alignment tool or reticle with a single engraved line. You need to get the lips of the drill balanced on either side of the center line.
The one on the right is the original, It's used to set the flat of a D bit vertical in the holder. Mine has a piece of polycarbonate with a fine line engraved on it.
It's used like this:
That's the head with an 1/8 collet holding a drill bit and my alignment tool in place instead of the stock one.
You line of the lips of the drill to the line:
It's pretty hard to take a picture of this but I think you get the idea.
Getting the bit properly aligned to the rotation scale allows you to rotate the bit a specific amount (1-2 deg) past the edge and then use a stop to grind the relief without risk of obliterating the edge.
I did the polycarbonate reticle (I think it's polycarbonate - you score both sides and it snaps cleanly) on my desktop CNC. The sheet is only .035 thick but stiff enough for this use. It machines engraves really well / easily. Using the CNC made it easy to get the engraved line to run right through the center of the mounting hole that the screw goes through. This one has an engraved line .003 deep with 30 deg V and .001 tip - the engraved width ends up at .0026 which is a little thick. It's easy to make another so I might see just how fine a line I can get.
The screw has an unthreaded shoulder that fits precisely in a counter bore of the shaft. There is a second threaded bore below that.
The shaft was held with collets, small end turned first, flipped around and the head bore and thread completed. This makes so the matching bore and screw shoulder are true to the shaft axis and this ensures that the reticle hole will also be concentric / true to the shaft. The CNC process engraves the line coincident with the mount hole and hence the shaft center.
I put a fair amount of thought into this relatively simple thing. Making it in a way that the geometry and construction just works. I started this morning creating a full CAD model - didn't really need to do that, but I needed a model for the reticle in order to cut it on my CNC so just did the whole thing - and then when a little overboard.
Just for yucks: I got to this because I had a project that I needed to drill lots of 1/8 holes. It will use up a bit or two by the time I'm done. So to do that I need to sharpen some of the ones I used up last time, and to sharpen the bits, I needed a better way to line them up.... So yes, this is Yack Shaving. (BTW - I've got perfectly good unused drill bits).
The one on the right is the original, It's used to set the flat of a D bit vertical in the holder. Mine has a piece of polycarbonate with a fine line engraved on it.
It's used like this:
That's the head with an 1/8 collet holding a drill bit and my alignment tool in place instead of the stock one.
You line of the lips of the drill to the line:
It's pretty hard to take a picture of this but I think you get the idea.
Getting the bit properly aligned to the rotation scale allows you to rotate the bit a specific amount (1-2 deg) past the edge and then use a stop to grind the relief without risk of obliterating the edge.
I did the polycarbonate reticle (I think it's polycarbonate - you score both sides and it snaps cleanly) on my desktop CNC. The sheet is only .035 thick but stiff enough for this use. It machines engraves really well / easily. Using the CNC made it easy to get the engraved line to run right through the center of the mounting hole that the screw goes through. This one has an engraved line .003 deep with 30 deg V and .001 tip - the engraved width ends up at .0026 which is a little thick. It's easy to make another so I might see just how fine a line I can get.
The screw has an unthreaded shoulder that fits precisely in a counter bore of the shaft. There is a second threaded bore below that.
The shaft was held with collets, small end turned first, flipped around and the head bore and thread completed. This makes so the matching bore and screw shoulder are true to the shaft axis and this ensures that the reticle hole will also be concentric / true to the shaft. The CNC process engraves the line coincident with the mount hole and hence the shaft center.
I put a fair amount of thought into this relatively simple thing. Making it in a way that the geometry and construction just works. I started this morning creating a full CAD model - didn't really need to do that, but I needed a model for the reticle in order to cut it on my CNC so just did the whole thing - and then when a little overboard.
Just for yucks: I got to this because I had a project that I needed to drill lots of 1/8 holes. It will use up a bit or two by the time I'm done. So to do that I need to sharpen some of the ones I used up last time, and to sharpen the bits, I needed a better way to line them up.... So yes, this is Yack Shaving. (BTW - I've got perfectly good unused drill bits).
